We were commissioned by RPS on behalf of Northern Irish Water to carry out nine outfall surveys on locations in and around the outskirts of Belfast to ascertain their condition and to measure silt & debris levels through a combination of CCTV imaging where water clarity would permit and profiling sonar.
The outfalls varied in diameter between 400mm diameter to 2000mm box section and outfall lengths varied between 150m and 1600m; all surveys were carried out under operational conditions which included torrential flows in access chamber, high turbulence and varying water depths which necessitated some surveys being carried out within a limited tidal window.
The scope was made all the more challenging by the widely varying locations, the variations in survey lengths, outfall dimensions and access restrictions, as a result of which we had to develop 3-launch systems to overcome site specific access challenges and deploy 5-different types of Pipe Inspection Vehicle (PIV) which included the design and build of a bespoke Micro-PIV.